I want to have a batch of new (unique) actor and their campsite appear once the player completes a certain quest stage. They should only exist in their base form before the scripts check is met and the player completes the quest stage. If this isn't possible then I am sure the next idea is....

Hide the new NPCs in an inn and attach a script to them that tells them to head to a location once the quest stage is complete. My only quandry with this is how would I get the NPC to stay there and maintain a basic eat,sleep,pray schedule?

Two words...

Initially Disabled

You could also just create an alias for those characters, and have a condition requiring your quest be past that stage for that alias to take effect.

1) Have the campsite initially disabled and enable parent on all the parts to an XMarker. Then, in the quest stages papyrus, enable that XMarker (and the campsite is there) at the time you want in the stage progression, then advance the quest by a stage (just leave it blank, it is just so the alias packages load right).

2) Make an alias for all of your characters that takes effect after the second stage is reached, and use

" Alias_CharacterAliasNameHere.GetRef().Moveto(Alias_LocationAliasNameHereLocREF.GetRef()) "

This moves the character that fills the character alias (CharacterAliasNameHere) to the location alias (LocationAliasNameHere).

A word of warning though, when you create character aliases, those characters MUST be enabled prior to the quest starting (otherwise the quest just won't start). And, since they must be enabled, you need a place to hide them before they fill that alias. If you want them doing something before they fill the alias then do that, but if you want them to only show after a certain point, hide them somewhere and give them a 'stand' package or something.

These pages are handy references:
http://www.creationkit.com/Bethesda_Tutorial_Planning_the_Quest
http://www.creationkit.com/Bethesda_Tutorial_Creating_an_Actor
http://www.creationkit.com/Bethesda_Tutorial_Quest_Aliases
http://www.creationkit.com/Bethesda_Tutorial_Basic_Quest_Scripting
http://www.creationkit.com/Category:Script_Objects
http://www.creationkit.com/Category:Events

Sorry for the link dump

Also, if you want them to stay in the campfire mode after the quest stage is reached, basically do the opposite, E.G. put them into an alias right away, and have a condition restricting that alias to before that point, and make their normal character packages do what you want them to do.